Ambient temperature inorganic electrolyte cells have generally employed lithium metal as the anode, high surface area carbon black as the cathode and a solution of lithium tetrachloroaluminate in thionyl chloride or sulfuryl chloride as the electrolyte. However, due to the low melting point of lithium metal (180.7 degrees C.), the lithium metal anode can melt under conditions when excessive heat is generated such as short circuit, forced overdischarge, etc. Molten lithium metal then can react with other components of the cell or discharge products such as elemental sulfur causing cell venting, cell rupture or under worst conditions cell explosions.
Attempts are, therefore, being made to find alternate anode materials for these cells. Thus, calcium metal which has a high melting point (839 degrees C.) has been successfully used as the anode material in calcium/thionyl chloride and calcium/sulfuryl chloride cells. The difficulty however, is that the open circuit voltage of calcium-sulfuryl chloride cells (3.2 volts) is much lower than the theoretically calculated value of 3.807 volts from the thermodynamic data. Thus, calcium/sulfuryl chloride cells operate much below their theoretical potential because of possible slow electrochemical kinetics of the calcium electrode.